BCS70 challenges stereotypes about only children

Mum and child

Family background matters more than being an only child when it comes to children’s development, according to evidence from BCS70 and three other studies.

It is often thought that only children’s cognitive development – the growth of knowledge, skills, and problem solving – is faster than that of their peers with siblings. The reason, supposedly, is that only children don’t have to share their parents’ attention and the family’s resources with brothers and sisters. As a result, they receive more attention and resources themselves, which in turn furthers their development.

But is this really the case?

New research based on the information you provided suggests that other factors may have a greater impact.

What we asked you

When you were 10 years old, you completed a special exercise in which you were asked to describe the similarities between different words. Your parents also told us whether you had any brothers or sisters.

Researchers from the Centre for Longitudinal Studies, which manages BCS70, compared the results of this word task for those who grew up with siblings and those without siblings. They found that, in these assessments, across all generations, only children had no advantage over those from two-child families. However, only children did do better than children growing up in households with three or more children.

Instead, things like family breakdown and financial struggles were more likely to impact a child’s cognitive development than whether they have brothers and sisters.

How are families changing?

Although only children did do better than children with two or more siblings, the so-called only child ‘advantage’ was less apparent in only children born at the turn of the century. Researchers believe this is because only-child families are changing.

Only children from your generation were more likely than previous generations to grow up with separated parents, with nearly a quarter having experienced family separation by age 10. This experience was more common for children born in 2001 – 58% of 11-year-olds without siblings in this generation did not live with both parents.

Why this research matters

For several reasons, only-child families are becoming more common around the globe. It’s important to challenge old stereotypes of only children so their differences are not overlooked in the way we support these children and their families.

This research was covered by The Conversation news site and translated into five languages. It’s reached millions of people across the world, from France, to Singapore, to Brazil!

Read the full research report

Only Children and Cognitive Ability in Childhood: A Cross-Cohort Analysis over 50 Years in the United Kingdom by Alice Goisis, Jenny Chanfreau, Vanessa Moulton, and George B. Ploubidis was published by Population and Development Review in May 2023.